EP3327457A1 - Medical imaging system comprising a magnet unit and a radiation unit - Google Patents

Abstract

The invention relates to a medical imaging system comprising a magnet unit (20) designed for magnetic resonance imaging of an examination object and a first radiation unit (30) designed to irradiate the examination subject, wherein the magnet unit comprises a main magnet and a housing, wherein the main magnet is disposed within the housing and wherein the main magnet coil elements and at least one coil carrier. Furthermore, the magnet unit defines such an examination opening (90) along an examination axis that the magnet unit encloses the examination opening. Furthermore, the magnet unit has a first region, which is transparent to radiation of the first radiation unit emitted radially to the examination axis. Furthermore, the first radiation unit is arranged on the side of the magnet unit facing away from the examination opening and designed to transmit radiation through the first area of the magnet unit in the direction of the examination opening. Furthermore, the first radiation unit is furthermore designed to rotate around the examination opening.

Description

Magnetic resonance imaging (MR) is an imaging procedure that is characterized by particularly high soft tissue contrast. It can therefore be used in particular in the diagnosis of tumors and in angiography.

In these application areas, it is also known to use radiation units such as X-ray sources or particle radiation sources. Particle radiation may be, in particular, electron radiation or hadron radiation. These radiation units can be used on the one hand together with a suitable detector for imaging, on the other hand for the manipulation of tissue.

For many medical diagnostic applications, it is desirable to use both MR image data and image data derived from radiation units. Furthermore, in the manipulation of tissue by means of particle radiation, it is desirable to monitor the position and other characteristics of the irradiated tissue by MR imaging.

It is known to carry out MR imaging and irradiation offset in time by means of an MR device and by means of a radiation device separate from the MR device. However, the patient must be transported or even relocated between the two different devices. Furthermore, the anatomy of the patient may change due to the time period between the two procedures, e.g. through breathing or metabolic processes. This complicates a combination of MR imaging with radiation.

From the publication US 2015/0247907 A1 It is known to operate an X-ray source and an X-ray detector in the examination opening of a magnetic resonance tomograph. For this, however, both the X-ray source and the X-ray detector must be designed to be operated in strong magnetic fields.

Furthermore, from the publication GANGULY, Arundhuti et al .: "Truly Hybrid X-Ray / MR Imaging: Toward a Streamlined Clinical System", in: Academic Radiology (12) 2005, pp. 1167-1177 It is known to use an MR apparatus having a plurality of magnet units and to form the radiation unit such that the beam path passes between the different magnet units. Although the radiation unit is not influenced by the strong magnetic field in the examination opening of the MR apparatus, it is difficult for the plurality of magnet units to achieve a homogeneous magnetic field in the examination opening which is necessary for MR imaging.

It is therefore the object of the present invention to provide an efficient possibility for a simultaneous MR imaging and radiation exposure of the examination subject.

The object is achieved by the medical imaging system according to the independent claim. Advantageous embodiments are described in the subclaims.

The invention relates to a medical imaging system, comprising a magnet unit designed for magnetic resonance imaging of an examination subject and a first radiation unit designed to irradiate the examination subject, wherein the magnet unit comprises a main magnet and a housing, wherein the main magnet is disposed within the housing and wherein the main magnet coil elements and at least having a bobbin. Furthermore, the magnet unit defines such an examination opening along an examination axis that the magnet unit encloses the examination opening. Furthermore, the magnet unit has a first region which is radial to the examination axis emitted radiation of the first radiation unit is transparent. Furthermore, the first radiation unit is arranged on the side of the magnet unit facing away from the examination opening and designed to transmit radiation through the first area of the magnet unit in the direction of the examination opening. Furthermore, the first radiation unit is furthermore designed to rotate around the examination opening.

The first region of the magnet unit is in particular so transparent to radiation of the first radiation unit that the intensity of radiation of the first radiation unit extending radially to the examination axis and through the first region is attenuated to a lesser extent than the intensity from radially to the examination axis and not through the first Area extending radiation of the first radiation unit. In particular, the attenuation of the intensity of the radiation passing through the first region after passing through the magnet unit is less than half or less than 10% or less than 1% of the attenuation of the intensity of the radiation not passing through the first region after passing through the magnet unit. The examination opening is designed in particular for receiving the examination subject. The first radiation unit can in particular be formed outside the magnet unit. The medical imaging system may in particular comprise exactly one magnet unit.

The inventors have recognized that the arrangement of the radiation unit outside the magnet unit does not influence it by the strong main magnetic field in the examination opening during the MR imaging. Therefore, inexpensive radiation units that are not designed to be operated in strong magnetic fields can be used.

As a further advantage of an arrangement of the first radiation unit outside the magnet unit in comparison to the arrangement In the examination opening, it follows that more space is available for the first radiation unit outside the magnet unit, and therefore more efficient and / or stronger first radiation units can be used. Furthermore, the inventors have recognized that by an arrangement outside the magnetic field, the first radiation unit is also very easily accessible for maintenance.

Furthermore, the inventors have recognized that it is not necessary to use a plurality of separated magnet units due to the region of the magnet unit that is transparent for the radiation of the first radiation unit. As a result, a more homogeneous magnetic field and thus a more accurate MR imaging can be achieved than with several separated magnet units.

According to a further possible aspect of the invention, the magnet unit further has a first exit area, which is transparent to radiation of the first radiation unit transmitted radially to the examination axis through the first area and the examination object, and wherein the first exit area does not overlap with the first area. The inventors have recognized that by means of an additional first exit region, on the one hand, a radiation detector can also be arranged outside the magnet unit. Furthermore, the unscattered radiation of the first radiation unit can be discharged from the magnet unit through a first exit area without interacting with the magnet unit and damaging it.

According to a further aspect of the invention, the coil elements of the main magnet and the at least one coil carrier are arranged outside the first region of the magnet unit. The inventors have recognized that, owing to this geometry of the coil elements and the coil carrier of the main magnet, transparency for the radiation of the radiation unit can be achieved particularly efficiently and cost-effectively, since no special materials are used for the coil elements of the main magnet and for the at least one coil carrier and no loss of intensity of the radiation in the transillumination of the coil elements of the main magnet or the at least one coil carrier occurs.

According to a further aspect of the invention, the magnet unit has in the first region at least one inner window and at least one outer window in the housing, wherein the inner window and the outer window are transparent to the radiation emitted by the first radiation unit. In this case, the inner window is arranged on the side of the magnet unit facing away from the examination opening, in particular as part of the housing. Furthermore, in this case, the outer window on the side facing away from the examination opening side of the magnet unit, in particular as part of the housing, is arranged. The inventors have recognized that by using at least two windows, the structure and thus the stability of the magnet unit can be obtained, and at the same time transparency of the first area of the magnet unit can be achieved.

In particular, the inner window and the outer window are so transparent that the material of the inner and outer windows for the radiation of the first radiation unit is more transparent than the material of the housing. In particular, the attenuation of the intensity of radiation as it passes through the window is less than half or less than 10% or less than 1% of the attenuation of the intensity as the housing passes.

According to a further aspect of the invention, the first region is formed as a funnel in the magnet unit, which extends radially to the examination axis and which is permeable to the radiation emitted by the first radiation unit radially to the examination axis. A funnel is in particular a through opening of the magnet unit. The inventors have realized that by using a funnel the radiation unit radiation transmitted by the magnet unit will be attenuated very little.

According to a further aspect of the invention, the funnel can be formed in particular by the housing of the magnet unit, in particular the side walls of the funnel can be formed by the housing. The inventors have recognized that the formation of the funnel through the housing makes it possible to form the magnet unit in a particularly stable manner, and in particular to design a closed cooling system as simply and inexpensively as possible.

According to a further aspect of the invention, the funnel can be filled in particular with a material transparent to the radiation of the first radiation unit. The inventors have recognized that the stability of the magnet unit can be increased by filling with a radiation-transmissive material.

According to another possible aspect of the invention, the medical imaging system further comprises a first radiation detector, wherein the first radiation detector is configured to detect radiation transmitted by the first radiation unit through the first region of the magnet unit, and wherein the first radiation detector is on the first radiation detector Radiation unit side facing away from the examination object is arranged. A first radiation detector may, in particular, be a first X-ray detector, a gamma detector and / or a particle detector. The inventors have recognized that detection of the radiation can be used to measure the radiation dose to which the examination subject is exposed by irradiation with the radiation of the first radiation unit, and thus to minimize the radiation dose.

According to another aspect of the invention, the first radiation unit is a particle source adapted to generate particle radiation. The inventors have realized that by irradiation by means of particle radiation particularly much energy can be deposited in a tissue, and the irradiation is therefore particularly effective.

According to another possible aspect of the invention, the particle source is adapted to generate electron and / or hadron radiation. The inventors have recognized that electron and / or hadron radiation can be generated in a particularly simple and cost-effective manner with a particle radiation source.

According to a further aspect of the invention, the first radiation unit is a first X-ray source. Furthermore, the medical imaging system has a first X-ray detector, wherein the first X-ray detector is arranged on the side of the examination subject facing away from the first X-ray source, and wherein the first X-ray source and the first X-ray detector are designed for X-ray imaging of the examination subject. The inventors have recognized that imaging is possible by means of X-radiation emitted by a first X-ray source and received by a first X-ray detector, which complements MR imaging well, because MR imaging has a good soft-tissue contrast, and X-ray imaging can be good bone structures and contrast agents.

The inventors have further recognized that an arrangement of the first X-ray source outside the magnet unit results in a larger distance and a smaller magnification factor of the X-ray projections than by an arrangement in the examination opening. As a result, the radiation dose absorbed by the surface of the examination object, in particular the skin of a patient, and the concealment of the x-ray projections are reduced.

According to a further aspect of the invention, the first X-ray detector can be arranged in the main magnetic field of the main magnet. The inventors have recognized that a first X-ray detector on the one hand, is clearly less sensitive to high magnetic fields than a first X-ray source, on the other hand, the arrangement in the main magnetic field, the X-rays must pass only once the main magnet, and no associated with an intensity attenuation second time. Therefore, in this arrangement, no exit region of the magnet unit for X-radiation must be transparent.

According to a further aspect of the invention, the first X-ray detector may be curved. The inventors have recognized that with a curved configuration, the space remaining in the examination opening for examination objects is greater, and / or a larger first X-ray detector can be used.

According to a further aspect of the invention, the magnet unit may have a first exit area, furthermore, the first x-ray detector outside the magnet unit is arranged on the side of the magnet unit facing away from the examination opening in front of the first exit area such that the first x-ray detector is moved from the first x-ray source through the first x-ray source Area emitted X-ray radiation can receive. The inventors have recognized that the arrangement of the first X-ray detector outside the magnet unit allows the examination opening to be made as large as possible.

According to a further aspect of the invention, the first X-ray detector is designed to rotate simultaneously with the first X-ray source around the examination opening. The inventors have recognized that by simultaneous rotation, the relative position between the first X-ray source and the first X-ray detector remains constant, and the X-ray imaging does not have to be adapted to a changed relative position. Furthermore, it is possible by the simultaneous rotation not to use a large, non-rotatable first X-ray detector, but a small and thus inexpensive first X-ray detector.

According to a further aspect of the invention, the magnet unit is designed to rotate about the examination opening. The inventors have recognized that, as a result, the first region of the magnet unit can be rotated in different orientations, and the irradiation can take place from different directions through only one transparent region of the magnet unit. Thus, the transparent area of the magnet unit only has to be as large as the beam path of the radiation unit. As a result of the smallest possible first area, the stability of the magnet unit increases, furthermore the coil elements of the main magnet and the coil carriers of the main magnet can be arranged in a larger volume, this simplifies the generation of a homogeneous magnetic field. Furthermore, the smallest possible first area simplifies the arrangement of a gradient coil unit and a high-frequency antenna unit outside the first area and thus improves the quality of the gradient field and the high-frequency field.

According to a further aspect of the invention, the first radiation unit and the magnet unit are designed to rotate simultaneously around the examination opening. In particular, the first radiation unit can be connected to the magnet unit. In particular, the first radiation unit may be connected to the magnet unit in such a way that the radiation emitted by the first radiation unit extends through the first transparent area of the magnet unit. The inventors have recognized that by simultaneous rotation of the first radiation unit with the magnet unit no separate, time-consuming alignment and / or placement of the first radiation unit during the examination is necessary. Furthermore, the first region of the magnet unit can be selected as small as possible. The inventors have further recognized that in this arrangement, the magnetic field of the main magnetic unit outside the inspection opening, which penetrates the first radiation unit, does not depend on the orientation of the first radiation unit. This can be done in the first Radiation unit measures are taken to compensate for the magnetic field, which do not depend on the orientation of the first radiation unit.

According to a further aspect of the invention, the magnet unit is designed to cool the coil elements of the main magnet by means of heat conduction. The inventors have recognized that cooling by means of heat conduction is more cost-effective than convection-based cooling by means of immersion in a coolant, since cooling by means of heat conduction requires less coolant. The inventors have further recognized that when cooling by means of heat conduction, the cooling performance is not or only less influenced by the orientation of the magnet unit than by cooling by means of immersion. This allows efficient cooling even with a magnet unit designed to rotate.

According to another aspect of the invention, the waste heat of the coil elements of the main magnet is diverted through conduits comprising circulating coolant. The inventors have recognized that a particularly effective cooling is possible by means of the pipes. Furthermore, the inventors have recognized that the first region can be formed in a particularly transparent manner for the radiation of the first radiation unit if the tube lines are arranged outside the first region of the magnet unit.

According to another aspect of the invention, the coil elements of the main magnet are formed of electrically superconductive material, wherein the critical temperature of the superconducting material is higher than the boiling point of helium. The inventors have recognized that by a critical temperature higher than the boiling point of liquid helium, coolants other than liquid helium and / or cooling methods can be used as an immersion in liquid helium, in particular cooling by means of heat conduction. This cooling is therefore more cost-effective and furthermore particularly advantageous in the case of a magnet unit designed to rotate This cooling is particularly advantageous in order to form the first region of the magnet unit transparent to the radiation of the first radiation unit.

According to another possible aspect of the invention, the electrically conductive material of the coil elements of the main magnet is magnesium diboride. The inventors have recognized that magnesium diboride is a metallic superconductor having a particularly high critical temperature. Thus, measures for cooling the coil elements can be used, which are particularly cost-effective and transparent to the radiation emitted by the radiation unit.

According to a further aspect of the invention, the medical imaging system further comprises a second radiation unit, wherein the second radiation unit is arranged on the side of the magnet unit facing away from the examination opening. Furthermore, the magnet unit has a second region which is transparent to radiation of the second radiation unit emitted radially to the examination axis. Furthermore, the second radiation unit is designed to transmit radiation through the second region of the magnet unit in the direction of the examination opening, furthermore, the second radiation unit is designed to rotate about the examination opening. In particular, the second beam unit can be arranged outside the magnet unit. The inventors have recognized that a second radiation unit that is present in addition to a first x-ray source can be irradiated with the second radiation unit based on the MR imaging and the x-ray imaging by means of the first x-ray source. As a result, the complementary image information of the MR imaging and the first X-ray imaging can be used. As a result, the second radiation unit can be used particularly efficiently.

The second region of the magnet unit is in particular so transparent to radiation of the second radiation unit that the intensity of radial to the examination axis and through the radiation of the second radiation unit extending to the second region is attenuated to a lesser extent than the intensity of radiation of the second radiation unit extending radially to the examination axis and not through the first region and not through the second region. In particular, the attenuation of the intensity of the radiation passing through the second region when passing is less than half or less than 10% or less than 1% of the attenuation of the intensity of the radiation not passing through the first and not the second region.

According to another aspect of the invention, the second radiation unit is a second X-ray source, furthermore, the medical imaging system has a second X-ray detector, wherein the second X-ray detector is arranged on the side of the examination subject which is remote from the second X-ray source. Furthermore, the second X-ray detector is designed to rotate simultaneously with the second X-ray source around the examination opening. Further, the second X-ray source and the second X-ray detector are formed for X-ray imaging of the examination subject. The inventors have recognized that with such an arrangement, it is possible to simultaneously record two X-ray projections from two different directions without having to perform rotation of the X-ray sources or rotation of the magnet unit , This makes it possible to reconstruct a three-dimensional X-ray image data set without rotation of the X-ray sources or a rotation of the magnet unit.

According to a further possible aspect of the invention, the magnet unit further has a second exit area, which is transparent to radiation of the second radiation unit transmitted radially to the examination axis through the second area and the examination object, wherein the second exit area does not overlap with the second area. The inventors have recognized that by means of an additional second exit region, on the one hand, a radiation detector can also be arranged outside the magnet unit. Furthermore, can be discharged through a second exit region, the unscattered radiation of the second radiation unit from the magnet unit without interacting with the magnet unit and damage it.

According to a further aspect of the invention, the second X-ray detector may have all further features of the first X-ray detector. All the advantages associated with an embodiment of the first X-ray detector can also be assigned to the corresponding embodiment of the second X-ray detector.

According to a further aspect of the invention, the second area of the magnet unit, the first exit area and / or the second exit area may have all further features of the first area of the magnet unit. All the advantages associated with an embodiment of the first region of the magnet unit can also be assigned to the corresponding embodiments of the second region, the first exit region and / or the second exit region.

According to a further aspect of the invention, the line connecting the first X-ray source and the first X-ray detector with the connecting line of the second X-ray source and the second X-ray detector forms an angle between 60 and 120 degrees or between 80 and 100 degrees or between 85 and 95 degrees. The inventors have recognized that the angle between the connecting lines corresponds to the angle between the projection directions of the X-ray projections recorded with the two X-ray sources and the two X-ray detectors. With such an angle between the X-ray projections, three-dimensional X-ray data from the two-dimensional X-ray projections can be reconstructed in a particularly efficient manner.

A magnet unit may in particular be cylindrical, annular and / or toroidal. Furthermore, the magnet unit has one of the examination opening facing Side, which is referred to as the inner side, further, the magnet unit has a side facing away from the examination opening, which is referred to as the outer side. The magnet unit encloses the examination opening in such a way that it encloses the examination opening along a circulation around the preferred direction, ie the examination opening is in particular open at two ends. The magnet unit also encloses an inspection opening when it has design-related recesses.

A radiation unit emits electromagnetic radiation or particle radiation. Electromagnetic radiation may in particular be X-radiation or gamma radiation. In particular, electromagnetic radiation having a wavelength of between 1 μm and 500 μm, in particular between 5 μm and 250 μm, in particular between 5 μm and 60 μm, is referred to as X-radiation. In particular, electromagnetic radiation having a wavelength of less than 5 μm, in particular less than 1 μm, is referred to as gamma radiation, regardless of the generation of the radiation. The spectrum of both X-rays and gamma rays can be monochromatic or polychromatic. In particular, particle radiation corresponds to a stream of particles in a common direction. Particles may in particular be leptons or baryons. Baryons may in particular be protons or neutrons. Leptons may in particular be electrons, positrons or muons.

A first region, a second region and / or an exit region of the magnet unit are transparent, in particular for the radiation of the first radiation unit, if the intensity of the radiation after passing through the first region, the second region and / or the exit region is at least 10%, in particular at least 50%, in particular at least 90%, in particular at least 95%, in particular at least 99%, in particular at least 99.9%, of the intensity of the radiation before passing through the first region, the second area and / or the exit area is. The magnet unit is more transparent, in particular for radiation of the first radiation unit extending radially to the examination axis and through the first area, the second area and / or the outlet area, than for the radiation extending radially to the examination axis and not through the first area, the second area and / or the exit area the first radiation unit, if the attenuation of the intensity of the radiation extending radially to the examination axis and not by the first region, the second region and / or the outlet region by more than a factor of 2, in particular by more than a factor of 5, in particular by more than one Factor 10, in particular by more than a factor 50, is greater than the attenuation of the intensity of the radiation extending radially to the examination axis and through the first region, the second region and / or the exit region. Here, the intensity denotes the energy of the radiation per unit area and per unit of time. In monochromatic electromagnetic radiation, the intensity of the radiation is particularly proportional to the quadratic amplitude of the variable electric field. In the case of particle radiation, the intensity of the radiation is, in particular, proportional to the energy of the particles and to the number of particles per unit of time.

In particular, a first unit and a second unit simultaneously rotate about an axis or a region as they rotate at the same angular velocity about the axis or region. In particular, therefore, the angle between the first connecting line of the first unit with the axis or the region and the second connecting line of the second unit with the axis or the region remains constant.

The cooling of the coil elements of a magnet can be effected by heat conduction, heat convection and / or thermal radiation. The coil elements of the main magnet of an MR device are designed, for example, for cooling by means of thermal convection, by being stored in liquid helium. Furthermore, the coil elements of the main magnet of an MR device can be designed for cooling by means of heat conduction.

Superconductors are materials whose electrical resistance falls below zero at a critical temperature (another technical term is the critical temperature). Superconducting materials are used in particular in coils and coil elements for generating strong magnetic fields.

A first unit, which is arranged on the side facing away from a second unit side of a third unit, does not have to be part of the third unit or be included by the third unit. In this case, a first unit is arranged behind the second unit, viewed in particular from the third unit, but in particular the first unit can also be fastened or arranged directly on the second unit. A first unit arranged on the side of a third unit facing a second unit does not have to be part of the third unit or be included in the third unit. In this case, a first unit is arranged in front of the second unit, in particular from the third unit, but in particular the first unit can also be fastened or arranged directly on the second unit.

In the following the invention will be described and explained in more detail with reference to the embodiments illustrated in the figures.

Fig. 1

eine perspektivische Ansicht eines medizinischen Bildgebungssystems,

Fig. 2

eine Magneteinheit mit einem inneren und einem äußeren Fenster,

Fig. 3

eine Magneteinheit mit einem Trichter,

Fig. 4

einen Schnitt durch das medizinische Bildgebungssystem senkrecht zur Untersuchungsachse,

Fig. 5

einen Schnitt durch das medizinische Bildgebungssystem senkrecht zur Untersuchungsachse, wobei die Magneteinheit gedreht wurde,

Fig. 6

einen Schnitt durch das medizinische Bildgebungssystem parallel zur Untersuchungsachse,

Fig. 7

einen Schnitt durch den Trichter einer Magneteinheit,

Fig. 8

einen Schnitt durch die Fenster einer Magneteinheit,

Fig. 9

ein medizinische Bildgebungssystem mit einer zweiten Röntgenquelle und einem zweiten Röntgendetektor,

Fig. 10

ein medizinisches Bildgebungssystem mit einer ersten Teilchenstrahlungseinheit umfassend einen Teilchenbeschleuniger und eine Teilchenstrahlführung,

Fig. 11

ein medizinisches Bildgebungssystem mit einer Teilchenstrahlungseinheit, wobei die Teilchenstrahlungseinheit elektrisch geladenen Teilchenstrahlung sendet.

Show it:

Fig. 1

a perspective view of a medical imaging system,

Fig. 2

a magnet unit with an inner and an outer window,

Fig. 3

a magnet unit with a funnel,

Fig. 4

a section through the medical imaging system perpendicular to the examination axis,

Fig. 5

a section through the medical imaging system perpendicular to the examination axis, wherein the magnet unit was rotated,

Fig. 6

a section through the medical imaging system parallel to the examination axis,

Fig. 7

a section through the funnel of a magnet unit,

Fig. 8

a section through the windows of a magnet unit,

Fig. 9

a medical imaging system having a second x-ray source and a second x-ray detector,

Fig. 10

a medical imaging system having a first particle radiation unit comprising a particle accelerator and a particle beam guide,

Fig. 11

a medical imaging system having a particle radiation unit, wherein the particle radiation unit transmits electrically charged particle radiation.

Fig. 1 shows a perspective view of a medical imaging system 10. In this embodiment, the medical imaging system 10 comprises a magnet unit 20, a first X-ray source 30, a storage and rotation device 40, an MR control and evaluation unit 50, an X-ray control and evaluation unit 60 and a storage device 70, on which an examination object 80 is located. The magnet unit 20 forms an examination opening 90, which is designed to receive the patient support device 70 with the patient 80.

In this embodiment, the magnet unit 20 is formed in the form of a hollow cylinder about an examination axis 91, the examination axis 91 extending parallel to a third coordinate axis z. Furthermore, a first coordinate axis x and a second coordinate axis y are shown, which together with the third coordinate axis z form a three-dimensional Cartesian coordinate system.

In this exemplary embodiment, the magnet unit 20 is rotatable about the examination opening 90, in particular rotatably around the examination axis 91, by means of the mounting and rotating device 40. At the same time, the first x-ray source 30 is fixedly connected to the magnet unit 20, so that upon rotation of the magnet unit 20 about the examination axis 91, the first x-ray source 30 is also rotated about the examination axis 91 and about the examination opening 90.

The magnet unit 20 is connected to the MR control and evaluation unit 50. The first radiation unit 30 is connected to the radiation control and evaluation unit 60. Furthermore, the MR control and evaluation unit 50 is connected to the radiation control and evaluation unit 60; in particular, the MR control and evaluation unit 50 and the radiation control and evaluation unit 60 can exchange image information and / or control signals with one another. It is also alternatively possible for the MR control and evaluation unit 50 and the radiation control and evaluation unit 60 to be designed in a common control and evaluation unit.

In the illustrated embodiment, the examination object 80 is a patient 80, and the storage device 70 is a patient support device 70. The patient support device 70 is adapted to transport the patient 80 into the cylindrically shaped examination opening 90.

Fig. 2 shows a magnet unit 20 with an outer window 25.1 and an inner window 25.2, wherein the windows are formed as part of the housing 26 of the magnet unit 20. In this embodiment, the first area of the magnet unit 20 is bounded by the outer window 25.1 and the inner window 25.2. The outer window 25.1 and the inner window 25.2 are here made of glass. However, the two windows 25.1, 25.2 can also be made of beryllium, aluminum or another material, the other material being transparent to the radiation 32 of the first radiation unit 30. In the illustrated embodiment, the outer window 25.1 and the inner window 25.2 is rectangular. However, the two windows 25.1, 25.2 can also be round, oval or in another form. In the design of the outer window 25.1 and the inner window 25.2, in particular the necessary stability of the magnet unit 20 and the geometric shape of the beam path of the radiation 32 of the first radiation unit 30 can be taken into account.

In the in Fig. 2 In the embodiment shown, the magnet unit 20 is designed to rotate around the examination axis 91 and only exactly a first area of the magnet unit 20 is bounded by the outer window 25.1 and the inner window 25.2. If the magnet unit 20 is not designed to rotate around the examination axis 91, it is alternatively possible to use a magnet unit 20 having a plurality of first areas and thus a plurality of outer windows 25.1 and inner windows 25.2, or a magnet unit 20 having a larger first area defined by To use a larger outer window 25.1 and a larger inner window 25.2 to radiate with the first radiation unit 30 from different directions on the object to be examined 80. In the embodiment shown are the outer Window 25.1 and the inner window 25.2 arcuately adapted to the curvature of the housing 26 of the magnet unit 20. It is also possible to use a flat outer window 25.1 and / or a flat inner window 25.2.

Fig. 3 shows a magnet unit 20, which forms a funnel 24 as a first region. The funnel 24 is formed in particular by the housing 26 of the magnet unit 20. The funnel 24 is formed in this embodiment as a prism with a rectangular base. However, the funnel 24 may also be formed as a prism with a different base area, or as a truncated pyramid or truncated cone. In particular, it is possible that the funnel 24 is cylindrical. In the design of the funnel 24, in particular the necessary stability of the magnet unit 20 and the geometric shape of the beam path of the radiation 32 of the first radiation unit 30 can be taken into account. In the illustrated embodiment, the hopper 24 is filled with air. However, it is also possible to fill the funnel 24 with another material that can be penetrated by the radiation 32 emitted by the first radiation unit 30. If the first radiation unit 30 is a first x-ray source 30, the funnel 24 can in particular also be filled with plexiglass.

In the in Fig. 3 In the embodiment shown, the magnet unit 20 is designed to rotate around the examination axis 91 and only exactly a first area of the magnet unit 20 is formed by a funnel 24. Alternatively, if the magnet unit 20 is not configured to rotate around the inspection axis 91, it is possible to use a magnet unit 20 having a plurality of first areas and thus multiple funnels 24, or a magnet unit 20 having a larger first area with a larger funnel 24 for irradiating the examination subject 80 with the first radiation unit 30 from different directions.

Fig. 4 shows a section through the medical imaging system 10 orthogonal to the examination axis 91, in particular a section through the magnet unit 20th Fig. 5 also shows a section through the medical imaging system 10 orthogonal to the examination axis 91, in particular a section through the magnet unit 20. In the illustrated embodiment, the magnet unit 20 is adapted to rotate, further, the first radiation unit 30 is fixedly connected to the magnet unit 20 and adapted to be common and to rotate simultaneously with the magnet unit 20 about the inspection opening 90. The orientation of the magnet unit 20 is given by a first rotated coordinate axis x 'and a second rotated coordinate axis y', the second rotated coordinate axis y 'being orthogonal to the first rotated coordinate axis x', and the first rotated coordinate axis x 'and the second rotated coordinate axis x' Coordinate axis y 'are orthogonal to the examination axis 91 and thus the third coordinate axis z. In the exemplary embodiment shown, the first radiation unit 30 corresponds to a first X-ray source, furthermore, the medical imaging system 10 comprises a first X-ray detector 31. It is, of course, also possible that the magnet unit 20 is connected to another first radiation unit 30 and at the same time configured to rotate about the examination axis 91 , In the illustrated embodiment of the Fig. 4 and the Fig. 5 the first X-ray detector 31 is designed to rotate simultaneously with the first X-ray source 30 and thus simultaneously with the magnet unit 20. Alternatively, the first X-ray detector 31 could also be stationary, in which case a significantly larger and / or a curved first X-ray detector 31 must be used in order to detect the X-ray radiation 32 of the first X-ray source 30 from different directions.

In the exemplary embodiment shown, the first radiation unit 30 is a first x-ray source 30, which is designed to transmit x-ray radiation 32. The first However, radiation unit 30 can also be designed to transmit gamma radiation or particle radiation.

In the exemplary embodiment shown, the first X-ray source 30 is designed as a first X-ray tube 30 with a rotating anode (an English technical term is "rotating anode"). A first x-ray tube 30 may in particular be formed together with a first x-ray detector 31 for x-ray imaging of the examination subject 80 by taking x-ray projections of the examination subject 80. In this case, a first x-ray tube with rotating anode and a first x-ray detector 31 are known from the prior art. By using a plurality of X-ray projections of an examination object with respect to different projection directions, a three-dimensional X-ray image data set can also be reconstructed.

Alternatively, a first X-ray source 30 may also be the first static anode X-ray tube ("static anode") or an liquid metal jet anode ("liquid metal jet anode"). Furthermore, a first X-ray source can be designed as a linear accelerator (an English technical term is "linear accelerator", short LINAC). In comparison with an X-ray tube, X-ray radiation having a smaller wavelength can be generated with a linear accelerator, in particular. This X-ray radiation can then be used in particular for the manipulation of a region of the examination object 80. It can be destroyed in particular by the irradiation tissue, especially tumor tissue. With a linear accelerator and particle radiation can be generated.

A linear accelerator has a linear acceleration unit formed along an axis. The linear acceleration unit may be formed parallel to the first rotated coordinate axis x '. The linear acceleration unit can also be designed in a different direction be, in particular parallel to the third coordinate axis z or parallel to the second rotated coordinate axis y '. In this case, the space requirement above the magnet unit 20 is particularly small, and the medical imaging system 10 can be used in standardized examination rooms, but with particle radiation then an additional deflection unit must be used to correct the radiation 32 through the first area of the magnet unit 20 send.

A first X-ray detector 31 may be formed flat as in the illustrated embodiment. Here, for a flat X-ray detector 31 different embodiments are known, for example consisting of amorphous silicon or consisting of complementary metal oxide semiconductors (an English term is "complementary metal oxide semiconductor", a common abbreviation is "CMOS"). Furthermore, photon counting first X-ray detectors as well as first X-ray detectors comprising a screen are known (a technical term is "screen-film"), wherein the screen converts X-ray radiation 32 into visible light. The first X-ray detector 31 may alternatively also be curved or piecewise curved.

The first X-ray detector 31 may, as in the embodiment shown, the Fig. 4 and Fig. 5 be formed within the examination opening 90. Furthermore, the X-ray detector can also be formed between the main magnet 21 and the examination opening 90, in particular between the parts or within the gradient coil unit 22 or the parts or within the high-frequency antenna unit 23. Alternatively, the first X-ray detector 31 can also be outside of the magnet unit 20 on the of the The first X-ray source facing away from the magnet unit 20 may be arranged. In this case, the magnet unit 20 has an outlet region 27 that is transparent to the radiation 32 of the first radiation unit 30, wherein the radiation 32 passes through the exit region 27 after the examination object 80 has passed.

In Fig. 6 the mode of operation of a magnet unit 20 is shown schematically on the basis of a section orthogonal to the second coordinate axis y. The magnet unit 20 encloses an examination opening 90 for receiving a patient 80. The examination opening 90 in the present exemplary embodiment has a cylindrical shape and is surrounded by a hollow cylinder in a circumferential direction by the magnet unit 20. In principle, however, a different design of the examination opening 90 is conceivable at any time. The patient 80 can be pushed into the examination opening 90 by means of a patient support device 70. For this purpose, the patient support device 70 has a patient table designed to be movable within the examination opening 90. The magnet unit 20 comprises a main magnet 21 for generating a strong and in particular homogeneous main magnetic field within the examination opening 90. The magnet unit 20 is shielded by means of a housing 26 to the outside.

The magnet unit 20 further includes a gradient coil unit 22 for generating magnetic field gradients used for spatial coding during imaging. The gradient coil unit 22 is controlled by means of a gradient control unit 53 of the MR control and evaluation unit 50. The magnet unit 20 furthermore comprises a high-frequency antenna unit 23, which in the present exemplary embodiment is designed as a body coil permanently integrated in the magnet unit 20. The high-frequency antenna unit 23 is designed to excite atomic nuclei established in the main magnetic field generated by the main magnet 21. The high-frequency antenna unit 23 is controlled by a high-frequency antenna control unit 52 of the MR control and evaluation unit 50 and radiates high-frequency alternating fields into an examination space, which is essentially formed by an examination opening 90 of the magnet unit 20. The high frequency antenna unit 23 is further configured to receive magnetic resonance signals.

In particular, the gradient coil unit 22 can generate magnetic fields with a gradient in the direction of the first rotated coordinate axis x ', in the direction of the second rotated coordinate axis y' or in the direction of the third coordinate axis y. For this purpose, the gradient coil unit 22 in this exemplary embodiment comprises three gradient coil subunits which can each generate a magnetic field with a gradient in the direction of one of the coordinate axes x ', y', z '. In this case, an arrangement is known for each of the three gradient coil unit units, so that each gradient coil unit unit is arranged outside the first area of the magnet unit 20.

For a control of the main magnet 21, the gradient coil unit 22 and for controlling the high-frequency antenna unit 23, the magnet unit 20 is connected to an MR control and evaluation unit 50. The MR control and evaluation unit 50 controls the magnet unit 20 centrally by means of a system control unit 51, such as, for example, carrying out a predetermined imaging gradient echo sequence. In this case, the control takes place via a high-frequency antenna control unit 52 and a gradient control unit 53. In addition, the MR control and evaluation unit 50 comprises an evaluation unit (not shown) for evaluating medical image data acquired during the magnetic resonance examination. Furthermore, the MR control and evaluation unit 50 comprises a user interface (not shown), which comprises a display unit 54 and an input unit 55, which are each connected to the system control unit 51. Control information, such as imaging parameters, as well as reconstructed magnetic resonance images may be displayed on the display unit 54, for example on at least one monitor, for a medical operator. By means of the input unit 55, information and / or parameters can be input during a measuring process by the medical operating personnel.

Fig. 7 shows a section orthogonal to the first rotated coordinate axis y 'through a funnel 24 through the magnet unit 20. In the illustrated embodiment, the funnel 24 passes through the main magnet 21 and the gradient coil unit 22, but not through the high-frequency antenna unit 23. In this embodiment, the high-frequency antenna unit 23 is at least partially formed permeable to radiation 32 of the first radiation unit 30. It is also possible that the funnel 24 penetrates the high-frequency antenna unit 23. Furthermore, it is also possible that the funnel 24 does not penetrate the gradient coil unit 22, in which case the gradient coil unit 22 must be at least partially permeable to radiation 32 of the first radiation unit 30. The funnel 24 penetrates the main magnet 21 in such a way that the main magnet 21, in particular the coil elements 21. 1, can generate a homogeneous magnetic field in the examination opening 90. In the exemplary embodiment shown, the main magnet 21 comprises a plurality of superconducting coil elements 21.1 on a coil support 21.2, which are surrounded by a coolant 21.3. The superconducting coil elements 21.1 in this case revolve around the examination opening 90. The coil support 21.2 on the one hand ensures the mechanical stability and the dimensional stability of the coil elements 21.1, as well as for the cooling of the coil elements 21.1.

Fig. 8 shows a section orthogonal to the first rotated coordinate axis y 'through the outer window 25.1 and the inner window 25.2 of the magnet unit 20. The outer window 25.1 and the inner window 25.2 are in the embodiment shown a part of the housing 26 of the magnet unit 20. Both the outer window 25.1 and the inner window 25.2 are rectangular here. Of course, other window shapes are possible, in particular round windows 25.1, 25.2. In this exemplary embodiment, the thermal insulation 21.4 likewise has regions 21.5 which are permeable to the radiation 32 of the first radiation unit 30. These areas 21.5 of the thermal insulation 21.4 For example, they may be constructed of the material of thermal insulation 21.4, but may be made thinner than the housing 26 outside the region. The regions 21.5 of the thermal insulation 21.4 can also be formed from a metal foil, in particular from an aluminum foil or a copper foil.

The outer window 25.1 and the inner window 25.2 consist in the illustrated embodiment of beryllium. It is also possible to form the windows 25.1, 25.2 of a different material that is transparent to the radiation 32 of the first radiation unit 30, for example made of aluminum or glass.

In the exemplary embodiment shown, the electrically conductive material of the coil elements 21.1 is magnesium diboride MgB ₂ . The critical temperature of 39 K of magnesium diboride MgB ₂ is above the boiling point of 4.2 K helium at atmospheric pressure 1013 hPa. There are also alternative electrically conductive materials for the coil elements 21.1 to imagine, especially superconducting materials, and especially superconducting materials having a critical temperature above the boiling point 4.2 K of helium at normal pressure 1013 hPa, for example niobium germanium Nb ₃ Ge with a critical temperature of 23 K.

Both in the in Fig. 7 as well as in the Fig. 8 illustrated embodiment, the cooling is carried out by heat conduction through the bobbin 21.2 by the bobbin 21.2 is cooled by means of a tube system, wherein circulated in the tube system, a coolant for heat transfer and the heat is transported to a heat exchanger. It can be supported by means of an optional gaseous coolant 21.3 cooled. That in the Fig. 7 not shown tube system is formed such that it is not formed in the first region of the magnet unit 20 in order to improve the transparency of the first region for radiation 32 of the first radiation unit 30. Alternatively and in particular When not designed for rotating magnetic units 20, the cooling of the coil elements 21.1 can be done by immersion in a coolant 21.3, for example, in liquid helium 21.3. Such a tube system is for example from the document DE 10 2004 061 869 B4 known.

Both in the in Fig. 7 as well as in the Fig. 8 illustrated embodiment, the coil elements 21.1 of the main magnet 21 and the bobbin 21.2 of the main magnet 21 are not arranged in the first region of the magnet unit 20. Also, no parts of the coil elements 21.1 and no parts of the coil support 21.2 are arranged in the first region of the magnet unit 20. In the case of a magnet unit 20, the coil elements 21.1 usually surround the examination axis 91 in a ring shape in order to generate a homogeneous magnetic field in the direction of the third coordinate axis z when current flows through the examination opening 90. The annular coil elements 21.1 are at a distance from one another with respect to the third coordinate axis z. In order that no parts of the coil elements 21.1 are formed in the first region of the magnet unit 20, a distance greater than the extent of the first region with respect to the third coordinate axis Z can be selected between two different coil elements 21.1, and the two different coil elements 21.1 can different sides of the first area are arranged. This distance may in particular be greater than the distances between all other adjacent coil elements 21.1. In the in Fig. 7 as well as in the Fig. 8 illustrated embodiment, the bobbin 21.2 forms in the first region of a through opening, which is greater than the extension of the beam path of the radiation 32 through the bobbin 21.2. Alternatively, it is conceivable to arrange at least one separate coil support 21.2 on different sides of the first region. Furthermore, it is also possible to use as the material of the coil carrier 21.2 a material that is transparent to the radiation 32 of the first radiation unit 30. The bobbin 21.2 is advantageously made of a material with high thermal conductivity and low mechanical deformability, in particular of metal, in particular of aluminum.

Fig. 9 11 shows a schematic section through a medical imaging system 10 with a first X-ray source 30, a second X-ray source 33, a first X-ray detector 31 and a second X-ray detector 34. In this case, the first X-ray source 30 is designed to receive X-radiation 32 through the magnet unit 20 and through the examination subject 80 in the direction of the first rotated coordinate axis x 'to the first x-ray detector 31, the second x-ray source 33 is designed to emit x-ray radiation 35 through the magnet unit 20 and through the examination subject 80 in the direction of the second rotated coordinate axis y' to the second x-ray detector 34. The rotated coordinate axis x 'is orthogonal to the rotated coordinate axis y', and both rotated coordinate axes are orthogonal to the examination axis 91 and thus to the coordinate axis z. By this arrangement, two X-ray projections with respect to orthogonal projection directions can be recorded simultaneously. With the two X-ray projections, a three-dimensional image data set can be reconstructed. In the embodiment shown, the magnet unit 20 is designed to rotate the examination opening 90, in particular about the examination axis 91. The first X-ray source 30, the first X-ray detector 31, the second X-ray source 33 and the second X-ray detector 34 are designed to rotate simultaneously with the magnet unit 20 around the examination opening 90, in particular around the examination axis 91, for example by being firmly connected to the magnet unit 20 are.

The connecting line between the first X-ray source 30 and the first X-ray detector 31 corresponds to FIG Fig. 9 of the coordinate axis x ', the connecting line between the second x-ray source 33 and the second x-ray detector 34 corresponds to the coordinate axis y'. In this embodiment, the connecting lines are orthogonal to each other, but other angles are possible.

Fig. 10 shows a schematic section through a medical imaging system 10 orthogonal to the second coordinate axis y. The medical imaging system 10 comprises, in addition to the magnet unit 20, a radiation unit 30 which comprises a particle accelerator 30.1 and a charged particle beam guide 30.2 for charged particles (an English term for a mobile particle beam guidance is "gantry"). In this exemplary embodiment, the particle accelerator 30. 1 is stationary, and the particle beam guide 30. 2 is designed to rotate the examination opening 90, in particular around the examination axis 91. Furthermore, in the exemplary embodiment shown, the magnet unit 20 is designed to rotate about the examination opening 90. In this case, the particle beam guide 30.2 and the magnet unit 20 are designed for simultaneous rotation. The movable particle beam guide 30.2 comprises deflection units which generate a magnetic field and, by means of the Lorentz force acting on charged particles, guide the particles to curves along the particle beam guidance 30.2. In this case, the strength of the magnetic fields of the particle beam guide 30.2 can be adapted to the mass, the charge and the velocity of the guided particles.

The medical imaging system 10 further comprises an exit region 27 and a shield 28 in this exemplary embodiment. The exit region 27 is configured such that the radiation 32 emitted by the radiation unit 30 through the funnel 24 onto the examination object 80 leaves the magnet unit 20 through the exit region 27. As a result, the particle radiation 32 can not damage the magnet unit 20. The shield 28, which is advantageously made of lead, absorbs the particle beam 32 in order to prevent a danger from the particle radiation 32.

In the exemplary embodiment shown, the exit region 27 of the magnet unit 20 is relative to the examination axis 91 the funnel 24 of the magnet unit 20 is arranged directly opposite. However, it is also possible to form the exit region 27 at another position, so that the deflection of the radiation 32 by the main magnetic field of the main magnet 21 is taken into account.

Fig. 11 shows a further section of the in Fig. 10 Since the main magnet 21, the gradient coil unit 22 and the high-frequency antenna unit 23 generate temporally constant or temporally variable magnetic or electric fields, radiation 32 consisting of electrically charged particles is deflected by the Lorentz force. In this example, the first radiation unit 30 is designed to adapt the speed and direction of the electrically charged particles in the particle beam 32 such that they strike a predefined part of the examination object 80, taking into account the electrical and magnetic fields prevailing in the examination opening 90.

In order to tune the particle radiation source 30 with the magnetic field of the magnet unit 20, the radiation control and evaluation unit 60 and the MR control and evaluation unit 50 are connected in this embodiment, while the MR control and evaluation unit 50 provides information about the magnetic field in the magnet unit 20 to the radiation control and evaluation unit 60, which adjusts the speed and direction of the particles of the particle radiation 32. However, it is also possible to execute the radiation control and evaluation unit 60 and the MR control and evaluation unit 50 as a common control and evaluation unit which controls both the magnet unit 20 and the first radiation unit 30 and evaluates the data obtained.

Furthermore, in the exemplary embodiment shown, the MR control and evaluation unit 50 transmits MR image data sets to the radiation control and evaluation unit 60. The radiation control and evaluation unit 60 can then transmit the radiation unit 30 so that the radiation 32 strikes a predetermined part of the examination object 80. A possible movement of the predetermined part of the examination object 80 due to changes or movements of the examination subject 80 can be detected by an analysis of the MR image data sets and compensated by means of the radiation control and evaluation unit 60.

Claims (15)

A medical imaging system (10) comprising a magnet unit (20) designed for magnetic resonance imaging of an examination object (80) and a first radiation unit (30) designed to irradiate the examination subject (80), - wherein the magnet unit (20) has a main magnet (21) and a housing (26), wherein the main magnet (21) within the housing (26) is arranged, and wherein the main magnet (21) coil elements (21.1) and at least one coil carrier (21.2), wherein the magnet unit (20) defines such an examination opening (90) along an examination axis (91) that the magnet unit (20) encloses the examination opening (90), - wherein the magnet unit (20) has a first region which is transparent to radiation (32) of the first radiation unit (30) emitted radially to the examination axis (91), - wherein the first radiation unit (30) is arranged on the side remote from the examination opening (90) side of the magnet unit (20), wherein the first radiation unit (30) is configured to transmit radiation (32) through the first area of the magnet unit (20) in the direction of the examination opening (90), - And wherein the first radiation unit (30) is further adapted to rotate around the examination opening (90). A medical imaging system (10) according to the preceding claim, wherein the coil elements (21.1) of the main magnet (21) and the at least one coil carrier (21.2) outside the first region of the magnet unit (20) are arranged. The medical imaging system (10) of any one of the preceding claims, wherein the magnet unit (20) is in the first region at least one inner window (25.2) and at least one outer window (25.1) in the housing (26), wherein the inner window (25.2) and the outer window (25.1) for the radiation (32) emitted by the first radiation unit (30) are transparent. A medical imaging system (10) according to claim 1 or 2, wherein the first region is formed as a funnel (24) in the magnet unit (20) extending radially to the examination axis (91) and radial to that of the first radiation unit (30) to the examination axis (91) emitted radiation (32) is transparent. The medical imaging system (10) of any preceding claim, wherein the first radiation unit (30) is a particle radiation source configured to generate particle radiation (32). A medical imaging system (10) according to any one of claims 1 to 3, - wherein the first radiation unit (30) is a first X-ray source (30), - wherein the medical imaging system (10) further comprises a first X-ray detector (31), wherein the first X-ray detector (31) is arranged on the side of the examination subject (80) which is remote from the first X-ray source (30), - And wherein the first X-ray source (30) and the first X-ray detector (31) for X-ray imaging of the examination object (80) are formed. The medical imaging system (10) of claim 6, wherein the first x-ray detector (31) is adapted to rotate simultaneously with the first x-ray source (30) about the examination port (90). The medical imaging system (10) of any one of the preceding claims, wherein the magnet unit (20) is adapted to rotate about the inspection port (90). The medical imaging system (10) of claim 8, wherein the first radiation unit (30) and the magnet unit (20) are configured to simultaneously rotate about the examination port (90). Medical imaging system (10) according to one of the preceding claims, wherein the magnet unit (20) is adapted to cool the coil elements (21.1) of the main magnet (21) by means of heat conduction. The medical imaging system (10) of claim 10 wherein the waste heat of the coil elements (21.1) of the main magnet (21) is dissipated through tubing comprising circulating coolant. A medical imaging system (10) according to any one of the preceding claims, wherein the coil elements (21.1) of the main magnet (21) are formed of electrically superconductive material, the critical temperature of the superconducting material being higher than the boiling point of helium. The medical imaging system (10) of any of claims 6 to 12, further comprising a second radiation unit (33), - wherein the magnet unit (20) has a second region, which is transparent to radiation (35) of the second radiation unit (33) emitted radially to the examination axis (91), wherein the second radiation unit (33) is arranged on the side of the magnet unit (20) facing away from the examination opening (90), - Wherein the second radiation unit (33) is adapted to radiation (35) through the second region of the magnet unit (20) towards the examination opening (90), - And wherein the second radiation unit (33) is further adapted to rotate around the examination opening (90). The medical imaging system (10) of claim 13, further comprising a second x-ray detector (34), - wherein the second radiation unit (33) is a second X-ray source (33), wherein the second X-ray detector (34) is arranged on the side of the examination subject (80) which is remote from the second X-ray source (33), wherein the second X-ray detector (34) is designed to rotate simultaneously with the second X-ray source (33) around the examination opening (90), - And wherein the second X-ray source (33) and the second X-ray detector (34) for X-ray imaging of the examination object (80) are formed. The medical imaging system (10) of claim 14, wherein the line of connection of the first x-ray source (30) and first x-ray detector (31) to the line of connection of the second x-ray source (33) and the second x-ray detector (34) is between 60 and 120 degrees or between 80 and 120 degrees 100 degrees or between 85 and 95 degrees.

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